An electronic device can integrate a touch sensor into a display to facilitate a user's interaction with elements shown on the display. When the user touches the display with one or more fingers, the touch sensor provides the location of each touch to the electronic device which, in turn, can cause elements shown on the display (such as icons, buttons, keys, toolbars, menus, pictures, sprites, applications, documents, canvases, maps, and so on) to change. In some instances, a user may prefer to interact with the display using an instrument that is more precise than the user's finger, such as a stylus.
However, a conventional stylus often provides only marginally enhanced precision to the user because conventional touch-sensitive electronic devices are configured, primarily, to detect the presence and location of the user's finger. For example, many conventional touch-sensitive electronic devices may be unable to reliably distinguish between input from the stylus and intentional or accidental input from the user's palm, wrist, or fingers.
In other cases, to accommodate stylus input, some conventional electronic devices may incorporate a separate input sensor, such as an electromagnetic digitizer, specifically dedicated to receiving input from a stylus that generates a magnetic field. However, these additional components often increase the cost and complexity of manufacturing of the electronic device, in addition to increasing the thickness and power consumption of the electronic device.